How to configure a web proxy for AutoSupport messages of OnCommandUnifiedManager 6.3?

I've a fresh installation of OnCommandUnifiedManager 6.3 - and that cannot send any AutoSupport messages directly to the technical support, because it has to use a web proxy for that - and I don't find any configuration entries to configure a web proxy. So, how do I configure a web proxy for the AutoSupport messages? Alternatively, I would like to switch to send the periodically AutoSupport messages by mail to the technical support - but also for that I don't find any configurations settings...